Patterning phase difference plate, production method for patterming phase difference plate, 2d/3d switching type liquid crystal display panel, and 2d/3d switching type liquid crystal display unit

ABSTRACT

First rubbing is performed on an entire surface of an alignment film ( 22 ) provided on a substrate ( 21 ), and then a mask part ( 51   a ) for masking a first region and a region of an alignment mark is formed on the alignment film ( 22 ) by using a resist layer ( 51 ). After performing second rubbing on the alignment film ( 22 ) through the mask part ( 51   a ), the mask part ( 51   a ) is removed, and a liquid crystal layer ( 23 ) is formed on the alignment film ( 22 ). In this way, the alignment mark is formed as a region having an optical function different from an optical function of a region surrounding the alignment mark.  
     Thus, it is possible to produce a substrate ( 21 ) having an alignment mark formed without increasing processing steps at such a position as to contact the liquid crystal layer ( 23 ).

TECHNICAL FIELD

The present invention relates to a patterning phase difference plate(for use in a 2D/3D switching type liquid crystal display panel and thelike) having an alignment mark, a production method for the patterningphase difference plate, a 2D/3D switching type liquid crystal displaypanel capable of switching between 2D display and 3D display, and aliquid crystal display unit.

BACKGROUND ART

In the production process for a liquid crystal display panel and thelike, two substrates for sandwiching a liquid crystal layer are producedseparately, and then bonded with each other. Usually, an alignment markis formed on each of the substrates, and the alignment mark is used foralignment in the process of bonding the substrates.

Conventionally, the alignment mark is formed by providing anexclusive-use film (which is exclusively for forming the alignment film)provided on an entire surface of the substrate under an alignment film,and patterning the exclusive-use film. Thus, formation of the alignmentmark increases processing steps.

In order to form the alignment mark without increasing the processingsteps, resist for forming a wiring pattern is used as the alignment markin Japanese Publication for Unexamined Patent Application, Tokukaihei1-92721 (publication date: Apr. 12, 1989).

According to a liquid crystal display unit in Japanese Publication forUnexamined Patent Application, Tokukaihei 1-92721 (publication date:Apr. 12, 1989), a mask part and an alignment mark part (a part to beused as the alignment mark) are formed simultaneously by using a resistlayer (which functions as a mask in patterning an ITO (Indium Tin Oxide)film (wire) by development). After the wiring pattern is formed bydevelopment, only the mask part of the resist layer is removed, and thealignment mark is left. The alignment mark is used later for alignment.

Meanwhile, in a 2D/3D switching type liquid crystal display panelproposed recently (see, for example, U.S. Pat. No. 6,046,849 (Date ofpatent: Apr. 4, 2000)), a patterning phase difference plate is used as aparallax barrier. The phase difference plate includes an alignment filmand a liquid crystal layer (which are provided on a substrate), and hasdifferent optical characteristics from region to region.

In producing the 2D/3D switching type liquid crystal display panel, itis necessary to align the patterning phase difference plate with aliquid crystal panel for generating a display image, and to bond thepatterning phase difference plate and the liquid crystal panel.Therefore, there is a need for a method that does not increase theprocessing steps even if the alignment mark of the patterning phasedifference plate is formed.

However, according to the arrangement of Japanese Publication forUnexamined Patent Application, Tokukaihei 1-92721 (publication date:Apr. 12, 1989), the resist layer, which is used for forming the wiringpattern, is also used for forming the alignment mark. Therefore, if thealignment mark is formed in a region where the liquid crystal layer isto be formed, the alignment mark remains as an inner surface of a cell(into which liquid crystal is to be injected) even after the substratesare bonded. As a result, the alignment mark directly contacts liquidcrystal injected into the cell.

By nature, the resist used as the alignment mark is not highly resistantto solvent medium. Therefore, if the alignment mark is formed in such aposition that the alignment mark directly contacts the liquid crystal,the resist is deformed by dissolving into the liquid crystal solution.This causes a problem that alignment cannot be performed at highaccuracy.

If the alignment mark formation method in Japanese Publication forUnexamined Patent Application, Tokukaihei 1-92721 (publication date:Apr. 12, 1989) is applied to a substrate for use in a liquid crystalpanel, the foregoing problem can be solved by forming the alignment markin a region other than the liquid crystal layer. However, the alignmentmark formation method in Japanese Publication for Unexamined PatentApplication, Tokukaihei 1-92721 (publication date: Apr. 12, 1989) cannotbe applied to the patterning phase difference plate in U.S. Pat. No.6,046,849 (Date of patent: Apr. 4, 2000), because the liquid crystallayer is formed on an entire surface of the substrate.

A person with an ordinary viewing field perceives images from twodifferent points of view, because two eyes of the person are spatiallyseparated from each other at the head. A human brain recognizes a 3Dobject from a parallax of the two images. By utilizing this mechanism, aliquid crystal display unit that performs 3D (three-dimensional) displayhas been developed. The 3D display is realized by causing a viewer tosee an image from two different points of view (the right eye and theleft eye) so as to generate a parallax.

In a liquid crystal display unit which performs 3D display, an image forthe left eye and an image for the right eye to be displayed on a displayscreen are encoded according to e.g. color, polarization state, ordisplay time, so as to supply images for different points of view toviewer's eyes. Then, the images are separated through aneye-glasses-type filtering system covering the viewer's eyes. In thisway, the image for the left eye is supplied to the left eye only, andthe image for the right eye is supplied to the right eye only.

In another liquid crystal display unit, a display panel 101 is combinedwith a parallax barrier 101 having a light-transmitting region and alight-shielding region arranged in a stripe shape. This allows a viewerto recognize a 3D image without using a visual assistance tool such asthe filtering system (automatic 3D display). To an image for the righteye and an image for the left eye, which are generated by the displaypanel 101, the parallax barrier 102 gives certain angles (see FIG.9(a)). From certain viewing regions in the space, the viewer canrecognize a 3D image because the right eye can see only the image forthe right eye, and the left eye can see only the image for the left eye(see FIG. 9(b)).

A liquid crystal display unit that performs automatic 3D display by thususing the parallax barrier is disclosed in U.S. Pat. No. 6,055,013 (Dateof patent: Apr. 25, 2000), for example. In U.S. Pat. No. 6,055,013 (Dateof patent: Apr. 25, 2000), a patterning phase difference plate is usedas the parallax barrier.

A liquid crystal display unit disclosed in e.g. U.S. Pat. No. 6,046,849(Date of patent: Apr. 4, 2000) includes the parallax barrier, and theliquid crystal display unit can electrically switch between 3D displayand 2D display (two-dimensional display) because the liquid crystaldisplay unit includes a switching liquid crystal layer or the like as ameans of switching between a state where an effect of the parallaxbarrier is enabled and a state where the effect of the parallax barrieris disabled. That is, in accordance with ON/OFF of the switching liquidcrystal layer, the unit of U.S. Pat. No. 6,046,849 (Date of patent: Apr.4, 2000) performs 3D display when the effect of the parallax barrier isenabled, and performs 2D display when the effect of the parallax barrieris disabled.

However, this arrangement of the conventional 2D/3D switching typeliquid crystal display unit has the following problem.

When the 2D/3D switching type liquid crystal display unit performs 3Ddisplay, light emitted from a light source passes through three activeareas, i.e. the switching liquid crystal layer, the parallax barrier,and a display liquid crystal layer (a liquid crystal layer forgenerating a display screen). Therefore, the 2D/3D switching type liquidcrystal display unit is realized by a transmissive liquid crystaldisplay unit.

When the 2D/3D switching type liquid crystal display unit performs 2Ddisplay, it remains to be the case that the light emitted from the lightsource passes through the three active areas, i.e. the switching liquidcrystal layer, the parallax barrier, and the display liquid crystallayer. The only difference is that the switching liquid crystal layerdisables the parallax barrier.

Thus, in the 2D/3D switching type liquid crystal display unit, both inperforming the 3D display and in performing the 2D display, the lightemitted from the light source passes through the switching liquidcrystal layer and the parallax barrier. Accordingly, light utilizationefficiency is lowered. Therefore, power of a light source used in the2D/3D switching type liquid crystal display unit needs to be higher thanthat of a light source used in a liquid crystal display unit whichperforms only 2D display or 3D display.

If a light source having higher power is used, it is particularly likelythat the temperature of the liquid crystal layer (the display liquidcrystal layer or the switching liquid crystal layer) provided closer tothe light source increases, often to such an extent as to be equal to orhigher than an ambient temperature. Therefore, there is a possibilitythat the liquid crystal layer provided closer to the light source doesnot function normally, thereby adversely affecting display operation,even at an ambient temperature which guarantees normal functions of thedisplay liquid crystal layer and the switching liquid crystal layer.

DISCLOSURE OF INVENTION

The present invention was made to solve the foregoing problem. An objectof the present invention is to provide a production method for apatterning phase difference plate, the method being such that analignment mark can be formed without increasing processing steps, evenif the alignment mark is formed at such a position as to contact theliquid crystal layer.

To attain the foregoing object, a patterning phase difference plate ofthe present invention includes an alignment film provided on a substratematerial, the alignment film having a first alignment region and asecond alignment region, the first alignment region and the secondalignment region having different alignment directions; a liquid crystallayer provided on the alignment film; and an alignment mark for use inbonding the patterning phase difference plate to another member, thealignment mark being a region having an optical function different froman optical function of a region surrounding the alignment mark.

According to this arrangement, the alignment mark has the opticalfunction different from the optical function of the region surroundingthe alignment mark. Specifically, the alignment film has differentalignment directions in the region of the alignment mark and in theregion surrounding the alignment mark. Therefore, after polarized lightis received in the vicinity of the alignment mark and transmittedthrough the liquid crystal layer of the patterning phase differenceplate, the polarized light is polarized differently through the regionof the alignment mark and the region surrounding the alignment mark(that is, polarization axes are different by 90°). The light transmittedin the vicinity of the alignment mark of the patterning phase differenceplate is detected after being transmitted through a polarizing platethat is so set as to have a transmission axis parallel to thepolarization axis of the light transmitted through the regionsurrounding the alignment mark. At this time, the polarizing plate cutsoff only the light radiated onto the region of the alignment mark. Thismakes it possible to detect the alignment mark.

Because the alignment mark is thus detected by utilizing opticalcharacteristics of the alignment film and a liquid crystal layer, nolayer for forming the alignment mark is provided. Therefore, unlike thecase where the alignment film is formed by using resist, there is nosuch problem that the alignment mark is dissolved by a liquid crystalsolution. As a result, the alignment mark of the patterning phasedifference plate can be formed without increasing the processing steps.

It is preferable if the patterning phase difference plate is such thatone of the first alignment region and the second alignment region isprovided in the region of the alignment mark, and the other of the firstalignment region and the second alignment region is provided in theregion surrounding the alignment mark.

According to the patterning phase difference plate arranged in thismanner, the alignment mark can be formed simultaneously when the firstalignment region and the second alignment region are formed.

To attain the foregoing object, a production method of the presentinvention for a patterning phase difference plate including an alignmentfilm provided on a substrate material, the alignment film having a firstalignment region and a second alignment region, the first alignmentregion and the second alignment region having different alignmentdirections; a liquid crystal layer provided on the alignment film; andan alignment mark for use in bonding the patterning phase differenceplate to another member, includes a first rubbing step, in which anentire surface of the alignment film provided on the substrate materialis rubbed so that the alignment direction of the first alignment regionis given to the entire surface of the alignment film; a mask formingstep, in which a resist layer is formed on the alignment film so as tomask (i) the first alignment region and (ii) the region of the alignmentmark or the region surrounding the alignment mark; a second rubbingstep, in which the alignment film is rubbed through the mask so that thealignment direction of the second alignment region is given to thealignment film; a mask removing step, in which the resist layer, whichhas been formed as a mask, is removed; and a liquid crystal layerforming step, in which the liquid crystal layer is formed on thealignment film.

According to this arrangement, a plurality of regions having differentalignment directions are formed on the alignment film by the firstrubbing step, the mask forming step, the second rubbing step, and themask removing step. Specifically, after the first rubbing step (in whichthe alignment direction of the first alignment region is given), apredetermined region is masked in the mask forming step, and the secondrubbing step (in which the alignment direction of the second alignmentregion is given) is performed through the mask. As a result, anon-masked region has the alignment direction of the second alignmentregion, and a masked region maintains the alignment direction of thefirst alignment region, and.

In the mask forming step, not only the first alignment region, but alsothe region of the alignment mark or the region surrounding the alignmentmark is masked. Therefore, the region of the alignment mark and theregion surrounding the alignment mark have different alignmentdirections. In the liquid crystal layer forming step, the liquid crystallayer is formed on the alignment film. In this way, the opticalcharacteristics of the patterning phase difference plate are attainedwithout causing the problem that the formation of the alignment markincreases the processing steps.

The present invention was made to solve the foregoing problem. An objectof the present invention is to provide a 2D/3D switching type liquidcrystal display unit capable of performing display operation withoutfail at an ambient temperature that guarantees operation.

To attain the foregoing object, a 2D/3D switching type liquid crystaldisplay panel of the present invention includes a display-use liquidcrystal panel capable of performing 2D display and 3D display, thedisplay-use liquid crystal panel generating a display image inaccordance with image data inputted; a parallax barrier which attains a3D effect by giving a certain viewing angle to the display image at atime of 3D display; and a switching liquid crystal panel which switchesbetween 2D display and 3D display by enabling or disabling an effect ofthe parallax barrier, one of (a) the display-use liquid crystal paneland (b) the switching liquid crystal panel being provided closer to alight source than the other, a liquid crystal layer in said one of (a)the display-use liquid crystal panel and (b) the switching liquidcrystal panel having a transition point higher than that of a liquidcrystal layer in the other.

To attain the foregoing object, a 2D/3D switching type liquid crystaldisplay unit of the present invention includes the 2D/3D switching typeliquid crystal display panel arranged in the foregoing manner.

According to this arrangement, because the liquid crystal layer in theliquid crystal panel provided closer to the light source has thetransition point higher than that of the liquid crystal layer in theliquid crystal panel provided farther from the light source, theoperation of the 2D/3D switching type liquid crystal display unit isguaranteed up to an ambient temperature close to the transition point ofthe liquid crystal panel provided farther from the light source, even ifthe temperature of the liquid crystal panel provided closer to the lightsource is higher than the ambient temperature due to the influence ofthe heat received from the light source.

For a fuller understanding of the nature and advantages of theinvention, reference should be made to the ensuing detailed descriptiontaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1(a) is a cross-sectional view illustrating a patterning phasedifference plate after the completion of first rubbing.

FIG. 1(b) is a cross-sectional view illustrating the patterning phasedifference plate after the formation of a resist layer.

FIG. 1(c) is a cross-sectional view illustrating the patterning phasedifference plate after the completion of first exposure, development,and drying.

FIG. 1(d) is a cross-sectional view illustrating the patterning phasedifference plate after the completion of second rubbing.

FIG. 1(e) is a cross-sectional view illustrating the patterning phasedifference plate after the completion of second exposure, development,and drying.

FIG. 1(f) is a cross-sectional view illustrating the patterning phasedifference plate after the formation of a liquid crystal layer.

FIG. 2 is a cross-sectional view illustrating a schematic arrangement ofa 2D/3D switching type liquid crystal display panel using the patterningphase difference plate.

FIG. 3(a) is a cross-sectional view of the patterning phase differenceplate.

FIG. 3(b) is a plan view of the patterning phase difference plate.

FIG. 3(c) is a plan view of the patterning phase difference plate afterthe formation of an alignment mark.

FIG. 4 is a diagram illustrating an optical axis direction at eachmember of the 2D/3D switching type liquid crystal display panel.

FIG. 5 is a flowchart showing assembly process for the 2D/3D switchingtype liquid crystal display panel.

FIG. 6 is a flowchart showing production process for the patterningphase difference plate.

FIG. 7 is a perspective view illustrating a schematic arrangement of analignment mark detection unit for detecting the alignment mark of thepatterning phase difference plate.

FIG. 8 is a diagram illustrating a method of detecting the alignmentmark of the patterning phase difference plate.

FIG. 9(a) is a diagram illustrating a mechanism of 3D display throughthe illustration of an effect of giving a viewing angle by a parallaxbarrier.

FIG. 9(b) is a diagram illustrating the mechanism of 3D display throughthe illustration of viewing regions for a 3D display screen.

BEST MODE FOR CARRYING OUT THE INVENTION

The following more specifically describes the present invention throughexamples and comparative examples. However, the present invention is notlimited by the examples and comparative examples.

With reference to FIGS. 1 through 8, one embodiment of the presentinvention is described below. First, a schematic arrangement of a 2D/3Dswitching type liquid crystal display panel using a patterning phasedifference plate of the present embodiment is described with referenceto FIG. 2.

As shown in FIG. 2, the 2D/3D switching type liquid crystal displaypanel includes a display-use liquid crystal panel 10, a patterning phasedifference plate 20, and a switching liquid crystal panel 30, which arebonded together.

The display-use liquid crystal panel 10 is a TFT liquid crystal displaypanel, and includes a first polarizing plate 11, an opposed substrate12, a liquid crystal layer 13, an active-matrix substrate 14, and asecond polarizing plate 15, which are laminated. Through a wire 51 suchas FPC (Flexible Printed Circuits), the active matrix substrate 14receives image data corresponding to an image to be displayed.

Thus, the display-use liquid crystal panel 10 is provided so that the2D/3D switching type liquid crystal display panel can generate a displayscreen corresponding to the image data. In other words, the display-useliquid crystal panel 10 is provided to the 2D/3D switching type liquidcrystal display panel as display image generating means for generating adisplay screen corresponding to the image data. As long as thedisplay-use liquid crystal panel 10 has a function of generating adisplay screen, a display method (a TN method or an STN method) and adriving method (active matrix driving or passive matrix driving) of thedisplay-use liquid crystal panel 10 are not particularly limited.

The patterning phase difference plate 20 functions as a part of aparallax barrier. As shown in FIG. 3(a), the patterning phase differenceplate 20 includes a transparent substrate 21, an alignment film 22, anda liquid crystal layer 23. The alignment film 22 is provided on thetransparent substrate 21, and the liquid crystal layer 23 is provided onthe alignment film 22. In an active area of the patterning phasedifference plate 20, as shown in FIG. 3(b), a first region 20A (shadedregion in the figure) and a second region 20B (dotted region in thefigure) are arranged alternately in a tripe shape. The first region 20Aand the second region 20B have different polarization states. Inaddition, as shown in FIG. 3(c), the patterning phase difference plate20 is provided with an alignment mark 20C formed by a production methoddescribed later.

The switching liquid crystal panel 30 includes a driver-side substrate31, a liquid crystal layer 32, an opposed substrate 33, and a thirdpolarizing plate 34, which are laminated. The driver-side substrate 31is connected to a wire 52. Through the wire 52, a driving voltage isapplied to the driver-side substrate 31 when the liquid crystal layer 32is ON.

The switching liquid crystal panel 30 is provided as switching means forswitching a polarization state of light (light transmitted through theswitching liquid crystal panel 30) in accordance with ON/OFF of theliquid crystal layer 32. Specifically, the switching liquid crystalpanel 30 optically modulates the light (light transmitted through theswitching liquid crystal panel 30) differently in performing 2D displayand in performing 3D display. Unlike the display-use liquid crystalpanel 10, the switching liquid crystal panel 30 does not have to bedriven by matrix driving. Driving electrodes of the driver-sidesubstrate 31 and of the opposed substrate 33 are formed on an entiresurface of an active area of the switching liquid crystal panel 30.

Described next is display operation of the 2D/3D switching type liquidcrystal display panel arranged in the foregoing manner.

To begin with, FIG. 4 illustrates an optical axis direction of eachmember of the 2D/3D switching type liquid crystal display panel shown inFIG. 2. The optical axis shown in FIG. 4 is directed in a direction of aslow phase axis of the alignment film (i.e. a rubbing direction for thealignment film) in the case of the liquid crystal panels and phasedifference plates, and in a direction of a transmission axis in the caseof the polarizing plates.

In the arrangement of FIG. 4, incident light emitted from a light sourceis firstly polarized by the third polarizing plate 34 of the switchingliquid crystal panel 30. When 3D display is performed, the switchingliquid crystal display panel 30 is OFF, and functions as a halfwavelength plate.

The light transmitted through the switching liquid crystal panel 30 isthen incident on the patterning phase difference plate 20. In the firstregion 20A and the second region 20B of the patterning phase differenceplate 20, rubbing directions (i.e. directions of slow axes) aredifferent. Therefore, light transmitted through the first region 20A andlight transmitted through the second region 20B are polarizeddifferently. In FIG. 4, the polarization axis of the light transmittedthrough the first region 20A and the polarization axis of the lighttransmitted through the second region 20B are different by 90°. Throughbirefringence ratio anisotropy and thickness of the liquid crystal layer23, the patterning phase difference plate 20 is set to function as ahalf wavelength plate.

The light transmitted through the patterning phase difference plate 20is incident on the second polarizing plate 15 of the display-use liquidcrystal panel 10. When 3D display is performed, the polarization axis ofthe light transmitted through the first region 20A of the patterningphase difference plate 20 is parallel to the transmission axis of thesecond polarizing plate 15. Therefore, the light transmitted through thefirst region 20A is transmitted through the polarizing plate 15. On theother hand, the polarization axis of the light transmitted through thesecond region 20B forms an angle of 90° with the transmission axis ofthe second polarizing plate 15. Therefore, the light transmitted throughthe second region 20B is not transmitted through the polarizing plate15.

According to the arrangement in FIG. 4, the function of parallax barrier(parallax barrier means) is attained by associated optical functions ofthe patterning phase difference plate 20 and the second polarizing plate(parallax barrier-use polarizing plate) 15. According to thisarrangement, the first region 20A of the patterning phase differenceplate 20 functions as a transmission region, and the second region 20Bof the patterning phase difference plate 20 functions as a cutoffregion.

The light transmitted through the second polarizing plate 15 isoptically modulated differently by a black-display pixel and awhite-display pixel in the liquid crystal layer 13 of the display-useliquid crystal panel 10. Only the light optically modulated by thewhite-display pixel is transmitted through the first polarizing plate11, thereby displaying an image.

At this time, the light angled at a certain viewing angle by beingtransmitted through the transmission region of the parallax barrier istransmitted through pixels in the display-use liquid crystal panel 10,the pixels respectively corresponding to an image for the right eye andan image for a left eye. As a result, the image for the right eye andthe image for the left eye are separated at different viewing angles, soas to perform 3D display.

In order to perform 2D display, the switching liquid crystal panel 30 isturned ON, so that the light transmitted through the switching liquidcrystal panel 30 will not be optically modulated. The light transmittedthrough the switching liquid crystal panel 30 is then transmittedthrough the patterning phase difference plate 20. The light transmittedthrough the first region 20A and the light transmitted through thesecond region 20B are polarized differently.

However, unlike in the case of 3D display, the switching liquid crystaldisplay panel 30 does not perform the function of optically modulatingthe light in the case of 2D display. Therefore, the polarization axes oflight beams transmitted through the patterning phase difference plate 20are angled symmetrically with respect to the transmission axis of thesecond polarizing plate 15. As a result, the light transmitted throughthe first region 20A of the patterning phase difference plate 20 and thelight transmitted through the second region 20B of the patterning phasedifference plate 20 are transmitted through the second polarizing plate15 at the same transmittance. Thus, the function of parallax barrier bythe associated optical functions of the patterning phase differenceplate 20 and the second polarizing plate 15 is not attained (that is,the certain viewing angle is not given), resulting in 2D display.

Next, assembly process for the 2D/3D switching type liquid crystaldisplay panel is described with reference to FIG. 5.

The 2D/3D switching type liquid crystal display panel of the presentembodiment is made by bonding the display-use liquid crystal panel 10,the patterning phase difference plate 20, and the switching liquidcrystal panel 30, which are produced separately.

As shown in FIG. 5, in the assembly process for the 2D/3D switching typeliquid crystal display panel, the patterning phase difference plate 20is bonded to the display-use liquid crystal panel 10 by using anadhesive agent (S1).

Then, the switching liquid crystal display panel 30 is bonded to thedisplay-use liquid crystal display panel 10, which is bonded with thepatterning phase difference plate 20, and the 2D/3D switching typeliquid crystal display panel is completed (S2 and S3).

In these bonding steps, alignment is performed by using an alignmentmark provided to each of the display-use liquid crystal panel 10, thepatterning phase difference plate 20, and the switching liquid crystalpanel 30. Therefore, the alignment mark is formed in each process ofproducing the display-use liquid crystal panel 10, the patterning phasedifference plate 20, and the switching liquid crystal panel 30.

A feature of the present invention is, in particular, the method offorming the alignment mark in the process of producing the patterningphase difference plate 20. The process of producing the patterning phasedifference plate 20 is described below with reference to FIG. 6 and FIG.1.

In the process of producing the patterning phase difference plate 20, asshown in FIG. 6, raw glass to be used as the substrate (substratematerial) 21 is cleansed, and polyimide is applied on one side of thecleansed substrate, and the substrate is then calcined, so as to formthe alignment film 22 (S11 to S13). Next, the alignment film 22 issubjected to first rubbing treatment (first rubbing; S14). The rubbingdirection in the first rubbing is the rubbing direction for the secondregion 20B. FIG. 1(a) illustrates the state of the phase differenceplate 20 after the completion of S11 to S14.

After the first rubbing, resist is applied onto the alignment film 22 ofthe cleansed substrate, and tentative calcination is performed, as to asform a resist layer 51 (S15 and S16). FIG. 1(b) illustrates the state ofthe phase difference plate 20 after the completion of S15 and S16.

After the resist layer 51 is formed, the resist layer 51 is patternedthrough the steps of exposing, developing, and drying (S17 and S18). Thepatterned resist layer 51 forms a mask part 51 a for masking a spot thatis to be the second region 20B of the patterning phase difference plate20. At those spots that are to be the first region 20 a and thealignment mark 20C of the patterning phase difference plate 20, thealignment layer 22 is exposed, because those spots are not covered withthe mask. FIG. 1(c) illustrates the state of the patterning phasedifference plate 20 after the completion of S17 to S18.

After the resist layer 51 is patterned, the substrate is subjected tosecond rubbing treatment (second rubbing) performed from the side of theresist layer 51 (S19). The rubbing direction in the second rubbing isthe rubbing direction for the first layer 20A. At this time, in thesecond region 20B, where the alignment film 22 is covered with the maskpart 51 a, the direction of the slow phase axis formed by the firstrubbing is maintained. On the other hand, in the first region 20A andthe alignment mark 20C, where the alignment film 22 is exposed (notcovered by the mask part 51 a), the slow phase axis is parallel to therubbing direction of the second rubbing. FIG. 1(d) illustrates the stateof the patterning phase difference plate 20 after the completion of S19.

After the second rubbing, the resist remaining on the alignment film 22of the cleansed substrate is exposed and developed again, so as toremove the mask part 51 a, and the patterning phase difference plate 20is then dried (S20 to S22). FIG. 1(e) illustrates the state of thepatterning phase difference plate 20 after the completion of S20 to S22.

After the mask part 51 a is removed, a UV curing type liquid crystalsolution is applied onto the alignment film 22 on the substrate by spincoating or the like method, and ultraviolet rays are radiated onto theUV curing type liquid crystal solution so as to bridge and polymerizeliquid crystal molecules (S23 and S24). As a result, the liquid crystallayer 23 is formed. FIG. 1(f) illustrates the state of the patterningphase difference plate 20 after the completion of S24.

S11 to S24 are performed in such a manner that a plurality of patterningphase difference plates 20 are formed on a single large-scale substrateat the same time. Therefore, production of the patterning phasedifference plate 20 is completed after dividing the substrate providedwith the plurality of patterning phase difference plates 20 intoindividual patterning phase difference plates 20, and testing theindividual patterning phase difference plates 20 (S25 to S27).

As described above, in the production method of the present embodimentfor the patterning phase difference plate 20, two regions havingdifferent alignment directions are formed on the alignment film 22 byforming a mask made of resist after the first rubbing, and performingthe second rubbing through the mask. No mask is provided in the regionwhere the alignment mark 20C is to be formed. Therefore, in thepatterning phase difference plate 20, the alignment direction in theregion of the alignment mask 20C is the same as the alignment directionin the first region 20A. In the region surrounding the alignment mark20C, the alignment direction is the same as the alignment direction inthe second region 20B.

Because the liquid crystal layer 23 is formed on the alignment film 22of the patterning phase difference plate 20, the light transmittedthrough the region of the alignment mark 20C and the light transmittedthrough the region surrounding the alignment mark 20C are polarizeddifferently. They are identical, however, in terms of light amount.Therefore, the alignment mark 20C cannot be detected by an ordinarymethod. However, the alignment mark 20C can be detected if the ordinarymethod is combined with a polarizing plate in an alignment markdetection unit.

With reference to FIGS. 7 and 8, the following describes a method ofdetecting the alignment mark 20C by using the alignment mark detectionunit. The alignment mark detection unit is used as an alignmentmechanism in a bonding device for bonding the patterning phasedifference plate 20 with another member (e.g. the display-use liquidcrystal panel 10).

In the alignment mark detection unit, as shown in FIG. 7, light emittedfrom a light source is transmitted through a light-source-sidepolarizing plate 61, and radiated onto the alignment mark 20C of thepatterning phase difference plate 20. The light transmitted through thepatterning phase difference plate 20 is transmitted through alight-receiving-section-side polarizing plate 62, and detected by alight-receiving section. Although not shown in FIG. 7, the alignmentmark of the aforesaid another member (the member to be aligned with thepatterning phase difference plate 20) is also positioned between thelight source and the light-receiving section. By detecting anoverlapping state of the alignment marks, the patterning phasedifference plate 20 and the aforesaid another member are aligned.

As shown in FIG. 8, the light transmitted through the light-source-sidepolarizing plate 61 (polarized light that is parallel to thetransmission axis direction of the light-source-side polarizing plate61) is incident on the patterning phase difference plate 20. There is adifference of 45° between the slow phase axis direction in the region ofthe alignment mark 20C and the slow phase axis direction in the regionsurrounding the alignment mark 20C. Therefore, there is a difference of90° between the polarization axis of the light transmitted through theregion of the alignment mark 20C and the polarization axis of the lighttransmitted through the region surrounding the alignment mark 20C.

The transmission axis direction of the light-receiving-section-sidepolarizing plate 62 is so set as to be parallel to the polarization axisof the light transmitted through the region surrounding the alignmentmark 20C. According to this arrangement, only the light radiated intothe region of the alignment mark 20C is cut off from the light to bereceived by the light-receiving section. Thus, the alignment mark 20Ccan be detected.

As described above, the patterning phase difference plate 20 of thepresent embodiment is such that the alignment mark 20C is detected byutilizing the optical characteristic of the alignment film 22 and theliquid crystal layer 23. There is no layer that is provided for formingthe alignment mark. Therefore, unlike the case where the alignment markis formed by using resist, there is no such problem that the alignmentmark dissolves in a liquid crystal solution. As a result, the alignmentmark of the patterning phase difference plate can be formed withoutincreasing the processing steps.

In the alignment mark detection unit, two polarizing plates need to beused in order to detect the alignment mark 20C of the patterning phasedifference plate 20. However, the provision of the polarizing plateshardly increases the cost for the alignment mark detection unit.

In the foregoing explanation, the alignment direction of the alignmentmark is identical to that of the second alignment region (in FIG. 3, thefirst region 20A), which is formed by the second rubbing. However, thealignment direction of the alignment mark may be identical to that ofthe first alignment region (in FIG. 3, the second region 20B), which isformed by the first rubbing. In this case, the alignment mark is maskedat the time of the first rubbing, while the region surrounding thealignment mark is exposed.

In the foregoing explanation, the present invention is described as amethod of forming the alignment mark of the patterning phase differenceplate. However, the present invention is applicable in other ways. Thepatterning phase difference plate is obtained by simultaneously forminga plurality of patterning phase difference plates on a large-scalesubstrate, and cutting each patterning phase difference plate off thelarge-scale substrate. In order to cut off the patterning phasedifference plate, a marker (mark for cutting) is required, and thepresent invention is applicable to the formation of the marker.

By providing a driving circuit, a backlight (light source), and the liketo the 2D/3D switching type liquid crystal display panel of the presentembodiment, a 2D/3D switching type liquid crystal display unit isprovided.

In the 2D/3D switching type liquid crystal display unit, the lightemitted from the light source is transmitted through the three activeareas, i.e. the display-use liquid crystal panel 10, the patterningphase difference plate 20, and the switching liquid crystal panel 30,both at the time of 3D display and at the time of 2D display. Due tocutoff and absorption in each active area, light utilization efficiencydecreases. In light of the drawback that the light utilizationefficiency is low, a high-power light source is used in the 2D/3Dswitching type liquid crystal display unit, so as to attain brightdisplay screen.

Thus, a high-power light source needs to be used in the 2D/3D switchingtype liquid crystal display unit. Therefore, a CCFT (Cold CathodeFluorescent Tube) or the like is more suitable as the light source thanan LED (Light Emitting Diode). However, because such a high-power lightsource generates a large amount of heat, the temperature of membersprovided close to the light source easily increases in the 2D/3Dswitching type liquid crystal display unit.

In the 2D/3D switching type liquid crystal display panel arranged asshown in FIG. 2, a transition point Tni1 of the display-use liquidcrystal panel 10 and a transition point Tni2 of the switching liquidcrystal panel 30 need to be equal to or higher than T1, which is atemperature that guarantees operation of the display-use liquid crystalpanel 10 and of the switching liquid crystal 30.

In reality, however, even if the transition point Tni1 of thedisplay-use liquid crystal panel 10 and the transition point Tni2 of theswitching liquid crystal panel 30 are set to be equal to or higher thanT1, an operating temperature of especially the liquid crystal panelprovided closer to the light source (in FIG. 2, the switching liquidcrystal panel 30) becomes equal to or higher than an ambienttemperature, due to the influence of heat received from the lightsource. Therefore, even if the ambient temperature is equal to or lowerthan T1, there is a possibility that the temperature of the switchingliquid crystal panel 30 exceeds the transition point thereof, therebyhindering normal display operation of the 2D/3D switching type liquidcrystal display unit.

To avoid this problem, the 2D/3D switching type liquid crystal displayunit of the present embodiment is designed so that the transition pointof one of the two kinds of display panels (the display-use liquidcrystal panel and the switching liquid crystal panel) is higher than thetransition point of the other of the two kinds of display panels, theone of the two kinds of display panels being the display panel providedcloser to the light source. In FIG. 2, the transition point Tni1 of theliquid crystal layer of the display-use liquid crystal panel 10 and thetransition point Tni2 of the liquid crystal layer of the switchingliquid crystal layer 30 are set so as to satisfy Tni1<Tni2. It ispreferable that the difference between Tni1 and Tni2 is 10° C. or more.

If the liquid crystal layer of the liquid crystal panel provided closerto the light source has a transition point higher than that of theliquid crystal layer of the liquid crystal panel provided farther fromthe light source, the operation of the 2D/3D switching type liquidcrystal display unit is guaranteed up to an ambient temperature close tothe transition point of the liquid crystal panel provided farther fromthe light source, even if the temperature of the liquid crystal panelprovided closer to the light source is higher than the ambienttemperature due to the influence of the heat received from the lightsource.

In the arrangement of FIG. 2, the switching liquid crystal panel 30 isthe liquid crystal panel provided closer to the light source. However,in the 2D/3D switching type liquid crystal display panel of the presentinvention, the display-use liquid crystal panel 10 may be the liquidcrystal panel provided closer to the light source. In this case, thedisplay-use liquid crystal panel 10, the switching liquid crystal panel30, and the patterning phase difference plate 20 are provided in thisorder from the side closer to the light source, and the relationshipbetween the transition point Tni1 of the liquid crystal layer of thedisplay-use liquid crystal panel 10 and the transition point Tni2 of theliquid crystal layer of the switching liquid crystal panel 30 isTni1>Tni2.

The invention being thus described, it will be obvious that the same waymay be varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

INDUSTRIAL APPLICABILITY

According to the arrangement or method of the present invention, thealignment mark can be formed without increasing processing steps at sucha position as to contact the liquid crystal layer. Therefore, thepresent invention can be suitably applied to a patterning phasedifference plate (for use in a 2D/3D switching type liquid crystaldisplay panel and the like) having an alignment mark, and to aproduction method for the patterning phase difference plate.

According to the arrangement of the present invention, display operationcan be performed without fail at an ambient temperature that guaranteesoperation. Therefore, the present invention is suitably applied to a2D/3D switching type liquid crystal display panel that allows forswitching between 2D display and 3D display, and to a liquid crystaldisplay unit.

1-8. (canceled)
 9. A patterning phase difference plate, comprising: analignment film provided on a substrate material, the alignment filmhaving a first alignment region and a second alignment region, the firstalignment region and the second alignment region having differentalignment directions; a liquid crystal layer provided on the alignmentfilm; and an alignment mark for use in bonding the patterning phasedifference plate to another member, one of the first alignment regionand the second alignment region being provided in the region of thealignment mark, the other of the first alignment region and the secondalignment region being provided in the region surrounding the alignmentmark.
 10. A liquid crystal display panel, comprising: a patterning phasedifference plate used as a parallax barrier, the patterning phasedifference plate including an alignment film provided on a substratematerial, the alignment film having a first alignment region and asecond alignment region, the first alignment region and the secondalignment region having different alignment directions; a liquid crystallayer provided on the alignment film; and an alignment mark for use inbonding the patterning phase difference plate to another member, one ofthe first alignment region and the second alignment region beingprovided in the region of the alignment mark, the other of the firstalignment region and the second alignment region being provided in theregion surrounding the alignment mark.
 11. A production method for apatterning phase difference plate including an alignment film providedon a substrate material, the alignment film having a first alignmentregion and a second alignment region, the first alignment region and thesecond alignment region having different alignment directions; a liquidcrystal layer provided on the alignment film; and time of 3D display;and a switching liquid crystal panel which switches between 2D displayand 3D display by enabling or disabling an effect of the parallaxbarrier, one of (a) the display-use liquid crystal panel and (b) theswitching liquid crystal panel being provided closer to a light sourcethan the other, a liquid crystal layer in said one of (a) thedisplay-use liquid crystal panel and (b) the switching liquid crystalpanel having a transition point higher than that of a liquid crystallayer in the other.
 12. A 2D/3D switching type liquid crystal displaypanel, comprising: a display-use liquid crystal panel capable ofperforming 2D display and 3D display, the display-use liquid crystalpanel generating a display image in accordance with image data inputted;a parallax barrier which attains a 3D effect by giving a certain viewingangle to the display image at a time of 3D display; and a switchingliquid crystal panel which switches between 2D display and 3D display byenabling or disabling an effect of the parallax barrier, one of (a) thedisplay-use liquid crystal panel and (b) the switching liquid crystalpanel being provided closer to a light source than the other, a liquidcrystal layer in said one of (a) the display-use liquid crystal paneland (b) the switching liquid crystal panel having a transition pointhigher than that of a liquid crystal layer in the other.
 13. A 2D/3Dswitching type liquid crystal display unit, comprising: 2D/3D switchingtype liquid crystal display panel including a display-use liquid crystalpanel capable of performing 2D display and 3D display, the display-useliquid crystal panel generating a display image in accordance with imagedata inputted; a parallax barrier which attains a 3D effect by giving acertain viewing angle to the display image at a time of 3D display; anda switching liquid crystal panel which switches between 2D display and3D display by enabling or disabling an effect of the parallax barrier,one of (a) the display-use liquid crystal panel and (b) the switchingliquid crystal panel being provided closer to a light source than theother, a liquid crystal layer in said one of (a) the display-use liquidcrystal panel and (b) the switching liquid crystal panel having atransition point higher than that of a liquid crystal layer in theother.
 14. A liquid crystal display panel, comprising: a display-useliquid crystal panel which generates two display images in accordancewith image data inputted; parallax barrier means which separates the twodisplay images into different viewing angles; and a switching liquidcrystal panel which enables or disables an effect of the parallaxbarrier means, one of (a) the display-use liquid crystal panel and (b)the switching liquid crystal panel being provided closer to a lightsource than the other, a liquid crystal layer in said one of (a) thedisplay-use liquid crystal panel and (b) the switching liquid crystalpanel having a transition point higher than that of a liquid crystallayer in the other.
 15. A liquid crystal display device, comprising: aliquid crystal display panel including a display-use liquid crystalpanel which generates two display images in accordance with image datainputted; parallax barrier means which separates the two display imagesinto different viewing angles; and a switching liquid crystal panelwhich enables or disables an effect of the parallax barrier means, oneof (a) the display-use liquid crystal panel and (b) the switching liquidcrystal panel being provided closer to a light source than the other, aliquid crystal layer in said one of (a) the display-use liquid crystalpanel and (b) the switching liquid crystal panel having a transitionpoint higher than that of a liquid crystal layer in the other.